Explosive charge with improved fragmentation effect

ABSTRACT

An explosive charge and method for producing increased fragmentation per unit weight of explosive by providing hollow bodies or cavities adjacent the explosive and connected to the explosive by means of a pipe. The explosive includes a channel communicating with the pipe. Any number of hollow bodies, spaced at any desired distance from the explosive, may be employed. The channel preferably is cylindrical or annular. Each hollow body may be filled with a gas, liquid or solid medium or be under vacuum.

IlnitedStates Patent Lingens et al.

[ Jan. 22, 1974 EXPLOSIVE CHARGE WITH IMPROVED FRAGMENTATION EFFECTFiled:

Inventors: Paul Lingens, Leverkusen; Garhard Martin, Troisdorf, both ofGermany Assignee: Dynamit Nobel Aktiengesellschaft,

Troisdorf, Germany July 25, 1970 July 26, 1971 Appl. No.: 166,191 n V t7 Foreign Application Priority Data Germany .2036977 US. Cl. 102/24 R,102/67 Int. Cl. F42h 3/00, F42b 13/48 Field of Search 102/22-24, 6, 65,

References Cited UNITED STATES PATENTS Burrows 102/66 767,776 l/l904Turner 102/22 1,554,827 9/1925 Pass l02/66 2,078,298 4/1937 White l02/22Primary ExaminerVerlin R. Pendegrass Attorney, Agent, or Firm-Craig,Antonelli & Hill 22 Claims, 3 Drawing Figures PATENTEDJMI 2 2 1974 FIGIINVENTORS PAUL LINGENS GERHARD MARTIN RM a ATTORNEYS EXPLOSIVE'CIIARGEWITH IMPROVED FRAGMENTATION EFFECT erably higherthan the detonationvelocity, i.e. such a gas flow then precedes the detonation front.

Ithas been found surprisingly that when the abovementioned gas currentsof high velocity and high energy density flow into cavities, chambers orhollow bodies, a high dynamic pressure with an extremely steep slope(surge front) is builtup therein, which pressure is sufficient tosplinter casings of considerable wall thickness around the cavities. Inthis connection, the gas flow can be conducted away from the explosiveto hollow spaces disposed outside of the explosive charge, throughpipelines of a corresponding strength.

Accordingly, this invention relates to an explosive device of increasedfragmentation effect, characterized by a chamber; filled with anexplosive from which one or more pipelines lead into cavities disposedexternally of the explosive charge and surrounded by the casing for the.explosive charge.

The cavities disposed outside of the explosive charge can be filled withgaseous and/or liquid and/or solid mediums. If a solid medium, it can bein pulverized form;

Additionally, this invention relates to a process for producing anincreased number of fragments in explosive devices, characterized inthat gas flows are conducted, via pipelines, from the explosive deviceinto cavities provided in the casing for the explosive charge.

Since the increase in pressure in such cavities takes place. withinextremely short periods of time, the pressure stress on the casing is ofa dynamic character, i.e. thestress corresponds to a very short-timepressure impulse or shock. This results in splinters or shrapnel havinga great velocity, and .thus a considerable piercing effect.

In "the explosive charge, an additionally provided bore for producingthe gaseous flow can exhibit any desired symmetrical as well asasymmetrical cross section or also an irregular boundary, and can varyover its length continuously or discontinuously.

As for the form of the cross section of the pipelines for conducting thegaseous flow into cavities outside of the explosive charge, the sameapplies as set forth above for the cross section of the bore in theexplosive device... Also, i the .pipelines need not be absolutelystraight; they can be, forexample, curved, or exhibit severalwknees, orany desired angle, or also the form of a spiral or helix.

With respect to the cavities into which the gas flow enters, it is of noimportance whether these cavities are under a vacuum or are filled withair or gas. An amplification of the pressure for disintegrating thecasing around the cavity can be effected by a filling of a flammable,explosive gas or gaseous mixture.

In general, the maximum cross section of the cavity will be adapted tothat of the explosive column, with respect to the area thereof. However,it can also be larger and smaller than this cross section. The volume ofthe hollow space is to be adapted to the energy and brisance of theexplosive and the length and cross section of the explosive column.

The gaseous stream can be conducted to the cavity through a pipeextending as much as desired into the cavity, or extending only from thesurface of the explosive into the cavity. The latter possibility,however, re sults in a somewhat diminished fragmentation effect. Thepipe need not be extended to the cavity absolutely in an axialorientation. Thus, for example, when the cavity is disposedgeometrically with respect to the explosive column (i.e., has the samecross section), the feed pipe can be arranged outside, but in parallel,to the axis of symmetry, or it can be at an angle to this axis.Furthermore, the feed pipe for the gaseous stream, insofar as it isextended into the cavity for a specific length, can exhibit a lesserstrength along this length.

In case of larger pipe lengths, it proved to be practicable to utilize apipe sealed at the end, which pipe extends to the bottom of the cavity,and besides to make the strength of the pipe section extending into thecavity lower than that of the remainder of the feed pipe. In thisarrangement, the shock pressure required for the fragmentation of thecasing is produced by a damming up of the gas flow in the pipe enddisposed in the cavity. As the transfer medium for the shock pressurefrom the pipe to the casing, preferably a liquid is employed, forexample, water, oil, etc., or a medium of a powdery or solidconsistency.

The invention will be explained in greater detail below with referenceto the embodiments illustrated in the drawings wherein:

FIG. 1 shows a cross section of an explosive device having cavities onboth sides externally of an explosive charge according to the invention;

FIG. 2 is a cross section of an explosive device exhibitingthree-serially disposed cavities outside of an explosive chargeaccording to the invention; and

FIG. 3 is a cross section of an explosive device having an annulararrangement according to the invention.

Referring to FIG. 1, cylindrical metallic body 1 is subdivided intothree chambers denoted by reference numerals 3, 4 and 5 by twopartitions 2. Of these chambers, central chamber 3 contains highexplosive l4, and chambers 4 and 5 contain non-explosive gas and/orliquid and/or solid mediums 15 and 16, respectively. Also, a pair ofsymmetrically-arranged bores 7 are provided in explosive chamber 3wherein the gas flow preceding the detonation front is formed and thenconducted through the pipes 10 into chambers 4 and 5.

The ignition of the explosive 14 in the center of chamber 3 is effectedby primer (or detonator) 13. If chamber 3 is large, several bores 7 maybe provided in the explosive column and with the associated pipelinesinto the chambers 4 and 5. When using respectively bores 7, as shown, inthe direction of the two sides of chamber 3, the bores need notabsolutely lie in the axis of the arrangement. Rather, the bores canalso be dis posed outside of the axis in parallel or at an anglethereto.

The explosive charge illustrated in FIG. 2 consists of cylindricalmetallic housing 1' subdivided into four chambers by three partitions 2.Chamber 3' is filled with a high explosive 14' and chambers 4', 5' and 6are filled with non-explosive gas and/or liquid and/or solid mediums l5,l6 and 17. Three pairs of bores 7', 8 and 9 are provided in explosivecolumn 3', wherein the gas currents preceding the detonation front areformed and then conducted, respectively, through pipes 10', l l and 12into the chambers 4, 5' and 6. By means of the primer 13', thedetonative reaction of the system is initiated.

The number of the chambers without explosive need not be restricted tothree, as shown in FIG. 2. The number is dependent on the length andcross section of the chamber filled with explosive. Also, a system canbe provided, analogous to FIG. 1, having chambers without explosivesdisposed on both ends of the chamber containing the explosive. In thiscase, the system is ignited in the center of the explosive column. Thecross sections of the individual chambers with and without explosive inthe structures illustrated in FIGS. 1 and 2 can, of course, also exhibitdifferent sizes and shapes.

It provided advantageous to fill the chambers without explosivesdirectly adjoining the explosive column with air and the chambersdisposed farther away with a transfer medium, e.g. water, oil, sand,etc. (Of course, as previously pointed out, these chambers, althoughdesignated nonexplosive, may contain a flammable, explosive gas orgaseous mixture.)

By fashioning the bores in the explosive column associated with theindividual chambers without explosive of different lengths, thechronological sequence of the fragmentation of the casing of thesechambers can be controlled within the time range of the reaction of theentire explosive column.

It is advisable to select the length of the bore in the explosive columnassociated with the first chamber in front of the explosive column to beshortest. For subsequent chambers, the lengths of the bores arepreferably increased in a stepped succession.

The individual bores in the explosive column according to FIG. 2 can,but need not, be disposed absolutely symmetrical and at equal spacingsfrom the central axis of the structure, and need not have the samediameter. The diameters of the bore can be varied within wide limits.Suitable values in this connection are those ranging between 1 and 50mm., preferably 4 and 8 mm.

In another geometric arrangement as shown in FIG. 3 the explosive columnconsists of two columns 18 and 19, one inserted in the other, the formerbeing hollow and the latter solid, and if an annular air gap 20 isprovided therebetween, a gas flow is formed in this interspace duringthe detonative reaction. (It should be pointed out that the crosssection of FIG. 2 is also representative of such an annular arrangement.Of course, pipes 10 and 12 are cross sections of a single annular pipeand thus are preferably of the same length.) This arrangement mayinclude not only a single annular channel but a plurality of suchchannels individually communicating with successively arranged separatecavities. As before, the gas flow precedes the detonation front and isaccompanied by a shock wave at the tip due to air compression. If thisgas flow is conducted into a cavity or chamber 21 without explosiveprovided at the end of the explosive column, a shock pressure isproduced therein by the dammed-up gas flow, which shock pressure bringsabout the splintering of the easing around the chamber. In order toincrease the shock pressure, it is advantageous to reduce the damming-up.space for the gas flow by continuing the solid explosive column intothe cavity by means of an inert section 22. By effecting the ignition ofthe explosive columns in the center, cavities can be provided on bothends of the column for the formation of additional splinters. If such acolumn is composed of several explosive columns with correspondingannular air gaps of the type indicated above, the inner column beingsolid and the others hollow, it is possible to provide several cavitieson both ends, similarly to the explosive charge device illustrated inFIG. 2. Each of these cavities is then associated with a specificannular air gap or channel.

The invention is not limited to annular or cylindrical gaps in thelongitudinal direction of the explosive columns for the formation of thegas flow. Such flows are formed in similar explosives having any typeand shape of gaps appropriately dimensioned to be utilized for thefragmentation of casings of cavities or chambers without increasing theamount of explosive.

To further amplify the nature of the invention, examples of variousembodiments are presented hereinafter. In the examples, to produce thegas flow, cylindrical bodies of composition B (39.5% by weight oftrinitrotoluene, 59.5% by weight of cyclotrimethylenetrinitramine and 1%by weight of wax) having a diameter of 30 mm. and a length of 140 mm.and an axial bore of a diameter of 10 mm. were employed. The explosivecharges were ignited at one end with the interposition of two shapedpenthrite charges of 18 g. (diameter 25 mm., length 50 mm.) by means ofan aluminum cap No. 8 (a blasting cap of aluminum with a primer pellet,a primary charge of 0.3 g. of lead tricinate and a secondary charge of0.8 g. of tetryl). The hollow chambers, cavities or bodies for theseexperiments were formed from two welded-together hexagonal threaded caps(1% inch; wall thickness 5 mm.; corner diameter of 58.5 mm.; height 54and 56 mm., respectively. The transfer pipes for the flow of gas fromthe explosive charge to the cavity (hollow body) were made of glass,synthetic resin, copper, and iron of an inside diameter of 10 mm.(Examples l-6 only) and different wall thicknesses. Each of the hollowbodies (or cavities) was provided on one end surface with a boredisposed centrally or eccentrically. This bore served for extending thepipeline into the hollow body. The outer diameter of the pipecorresponded to that of the bore. As indicator for the fragmentation,iron barrels were utilized; the hollow bodies were disposed in the axialcenter line of these barrels. From the penetration of the barrel by thefragments, a conclusion could be drawn with respect to the number andsize of the splinters produced by the disintegration of the hollowbodies.

EXAMPLE I A hollow body having an air filling was positioned immediatelyadjacent the explosive column and connected therewith by a glass pipe.to I00 fragments of up to 6 cm. resulted.

EXAMPLE 2 A hollow body with an air filling was spaced 50 mm. from theexplosive column by a connecting pipe of glass. The explosion produced80-90 fragments of up to 6 cm.

EXAMPLE 3 A hollow body with a sand filling was located mm. from theexplosive column by a connecting pipe of copper. Upon detonation, 70-80fragments of up to 6 cm. resulted:

EXAMPLE 4 A hollow body filled with water was spaced 150 mm. from theexplosive column by a connecting pipe of ironuThe explosion created70-80 fragments of up to 6 cm.

EXAMPLE 5 A hollow body with an oil filling was disposed 300 mm. fromthe explosive column via a glass connecting pipe. The result was 60-70fragments of up to 8 cm.

EXAMPLE 6 A hollow body filled with water at a spacing of 450 mmyfromthe explosive column together with a glass connecting pipe, wasemployed. The number of fragments, which ranged up to cm., was 30-40.

EXAMPLE 7 EXAMPLE 8 Three adjacently disposed hollow bodies were provided, of which the first having an air filling was in direct contactwith the explosive column. The two other hollow bodies, howver, werefilled with water. The explosive column had a diameter of 50 mm. andthree parallel, symmetrically-disposed longitudinal bores of a diameterof 8 mm. Each of the hollow bodies was in communication with,respectively, one of the three bores in the explosive charge, by meansof a steel tube. The steel tubes were passed through the bodies.

In the detonative reaction of the explosive column, all three hollowbodies were separated into a large number of splinters (150-200). Thefragments had a size of up to mm.

Needless to say, the devices of the examples are merely representativeof embodiments of the invention and may be modified in many ways. Forexample, hollow bodies can be disposed on opposite ends of the explosivecolumn with an appropriate extension of the column and a provision forcentral ignition.

Furthermore, the. technique of central ignition of a straight explosivecolumn can be broadened to twodimensional or three-dimensionalarrangements.

The present invention can be applied, in particular, to such explosivecharges which are provided with cavitiesanyway, e.g. for theaccommodation of electronic elements, such as in rocket warheads or thelike. The same effect will be obtained, as previously described. Thewalls surrounding the cavities will be splintered so that a largernumber of fragments, and thus a greater efficiency of the explosivecharge for antipersonnel or like uses, result.

The present invention is not limited to the embodiments and detailsshown and described herein but intended to cover changes andmodifications apparent to a person skilled in the art within the scopeof the invention.

We claim:

1. A fragmentation device for producing splinters comprising a containerformed of a material to produce splinters when subject to an explosiveforce, a chamber in said container filled with an explosive charge, andmeans for producing an increased splintering of said container, saidmeans including at least one cavity disposed within said containeroutside said chamber, and channel means communicating between saidchamber and said at least one cavity for conducting gas flow in responseto ignition of said explosive charge from said chamber to said at leastone cavity to cause increased splintering of said container.

2. A device according to claim 1 wherein said at least one cavity isfilled with a medium and said container is formed of a metallicmaterial.

3. A device according to claim 2 wherein said medium is one of anon-explosive liquid and solid.

4. A device according to claim 2 wherein said medium is one of aflammable and explosive gas.

5. A device according to claim 1 wherein said explosive charge includesat least one passageway therein which communicates with said channelmeans.

6. A device according to claim 5 wherein said channel means comprises atleast one pipeline and said passageway is a bore.

7. A device according to claim 6 wherein said at least one pipeline andbore are substantially cylindrically shaped.

8. A device according to claim 5 wherein said channel means and said atleast one passageway are annularly shaped.

9. A device according to claim 8 wherein said explosive charge comprisesan inner cylindrical body and an annular body concentrically arrangedtherearound, said bodies being separated by the annular-shapedpassageway.

10. A device according to claim 5 wherein said channel means has asealed-off end which terminates within said at least one cavity.

11. A device according to claim 10 wherein said channel means passessubstantially through said at least one cavity and the sealed-0E endthereof terminates in the vicinity of a wall of said at least onecavity.

12. A device according to claim 11 wherein said container, chamber andat least one cavity are substantially cylindrically shaped and saidsealed-off end of said channel means is disposed near the wall of saidat least one cavity opposite said chamber.

13. A device according to claim 2 wherein said at least one cavitycomprises a plurality of cavities serially-arranged with respect to eachother, the first of said cavities abutting said chamber, said channelmeans comprising a plurality of channels each communicating respectivelybetween a cavity and said chamber.

14. A device according to claim 2 wherein said at least one cavityincludes at least two cavities, each disposed on opposite sides of saidchamber.

15. A device according to claim 14 further comprising a central primerdisposed within said explosive charge between said cavities.

16. A process for the production of an increased number of splinters ofa fragmentation device having a container formed of a material toproduce splinters when subjected to an explosive force and having anexplosive charge filling a chamber disposed within the container,comprising producing an increased splintering of the container bydisposing at least one cavity within the container outside of thechamber, igniting the explosive charge within the chamber, andconducting the gas flow resulting from the ignition of the explosivecharge from the chamber into the at least one cavity to cause increasedsplintering of the container.

17. A process according to claim 16 wherein said gas flow is channeledthrough a narrow passageway and expanded into said at least one cavity.

18. A process according to claim 16 wherein said gas flow is directedthrough at least one pipeline into said at least one cavity.

19. A process according to claim 18 wherein said gas flow is conductedthrough at least one bore in said explosive charge into said at leastone pipeline.

20. An explosive device producing increased fragmentation upondetonation comprising a substantially cylindrical fragmentablecontainer, a chamber including an outer annular explosive body and aninner cylindrical explosive body disposed within said outer annularexplosive body, said explosive bodies being separated by anannular-shaped passageway, at least one cylindrical cavity disposedwithin said container and abutting said chamber and channel meanscommunicating between the annular-shaped passageway and said at leastone cavity for conducting gas flow from said chamber to said at leastone cavity in response to ignition of said explosive bodies for causingincreased fragmentation of said container.

21. An explosive device according to claim 20 wherein said channel meansis a cylindrically shaped pipe having one end communicating with theannularshaped passageway while the other end is sealed-off.

22. An explosive device according to claim 21 wherein an inert,non-explosive cylindrical body of a diameter corresponding to thediameter of said inner cylindrical explosive body is disposedconcentrically inside said channel means and abuts at opposite endsthereof said inner cylindrical explosive body and the closed-off end ofsaid pipe.

1. A fragmentation device for producing splinters comprising a containerformed of a material to produce splinters when subject to an explosiveforce, a chamber in said container filled with an explosive charge, andmeans for producing an increased splintering of said container, saidmeans including at least one cavity disposed within said containeroutside said chamber, and channel means communicating between saidchamber and said at least one cavity for conducting gas flow in responseto ignition of said explosive charge from said chamber to said at leastone cavity to cause increased splintering of said container.
 2. A deviceaccording to claim 1 wherein said at least one cavity is filled with amedium and said container is formed of a metallic material.
 3. A deviceaccording to claim 2 wherein said medium is one of a non-explosiveliquid and solid.
 4. A device according to claim 2 wherein said mediumis one of a flammable and explosive gas.
 5. A device according to claim1 wherein said explosive charge includes at least one passageway thereinwhich communicates with said channel means.
 6. A device according toclaim 5 wherein said channel means comprises at least one pipeline andsaid passageway is a bore.
 7. A device according to claim 6 wherein saidat least one pipeline and bore are substantially cylindrically shaped.8. A device according to claim 5 wherein said channel means and said atleast one passageway are annularly shaped.
 9. A device according toclaim 8 wherein said explosive charge comprises an inner cylindricalbody and an annular body concentrically arranged therearound, saidbodies being separated by the annular-shaped passageway.
 10. A deviceaccording to claim 5 wherein said channel means has a sealed-off endwhich terminates within said at least one cavity.
 11. A device accordingto claim 10 wherein said channel means passes substantially through saidat least one cavity and the sealed-off end thereof terminates in thevicinity of a wall of said at least one cavity.
 12. A device accordingto claim 11 wherein said container, chamber and at least one cavity aresubstantially cylindrically shaped and said sealed-off end of saidchannel means is disposed near the wall of said at least one cavityopposite said chamber.
 13. A device according to claim 2 wherein said atleast one cavity comprises a plurality of cavities serially-arrangedwith respect to each other, the first of said cavities abutting saidchamber, said channel means comprising a plurality of channels eachcommunicating respectively between a cavity and said chamber.
 14. Adevice according to claim 2 wherein said at least one cavity includes atleast two cavities, each disposed on opposite sides of said chamber. 15.A device according to claim 14 further comprising a central primerdisposed within said explosive charge between said cavities.
 16. Aprocess for the production of an increased number of splinters of afragmentation device having a container formed of a material to producesplinters when subjected to an explosive force and having an explosivecharge filling a chamber disposed within the container, comprisingproducing an increased splintering of the container by disposing atleast one cavity within the container outside of the chamber, ignitingthe explosive charge within the chamber, and conducting the gas flowresulting from the ignition of the explosive charge from the chamberinto the at least one cavity to cause increased splintering of thecontainer.
 17. A process according to claim 16 wherein said gas flow ischanneled through a narrow passageway and expanded into said at leastone cavity.
 18. A process according to claim 16 wherein said gas flow isdirected through at least one pipeline into said at least one cavity.19. A process according to claim 18 wherein said gas flow is conductedthrough at least one bore in said explosive charge into said at leastone pipeline.
 20. An explosive device producing increased fragmentationupon detonation comprising a substantially cylindrical fragmentablecontainer, a chamber including an outer annular explosive body and aninner cylindrical explosive body disposed within said outer annularexplosive body, said explosive bodies being separated by anannular-shaped passageway, at least one cylindrical cavity disposedwithin said container and abutting said chamber and channel meanscommunicating between the annular-shaped passageway and said at leastone cavity for conducting gas flow from said chamber to said at leastone cavity in response to ignition of said explosive bodies for causingincreased fragmentation of said container.
 21. An explosive deviceaccording to claim 20 wherein said channel means is a cylindricallyshaped pipe having one end communicating with the annular-shapedpassageway while the other end is sealed-off.
 22. An explosive deviceaccording to claim 21 wherein an inert, non-explosive cylindrical bodyof a diameter corresponding to the diameter of said inner cylindricalexplosive body is disposed concentrically inside said channel means andabuts at opposite ends thereof said inner cylindrical explosive body andthe closed-off end of said pipe.